Magnetic toy

ABSTRACT

A magnetic toy having two separate parts: a first part comprising a single magnet and a second part comprising a plurality of magnets held in fixed configuration to one another, and the relative strengths of the magnets being such that as the first part is moved towards the second part the magnetic force between the two parts will initially result in attraction of the two parts but at some point as the two parts become closer the direction of the magnetic force between the parts will reverse resulting in the two parts repelling one-another.

FIELD OF INVENTION

The present invention relates to a magnetic toy.

BACKGROUND OF INVENTION

Toys that make use of the attraction force between magnets with unlike poles are well known as are toys having single magnets that attract ferro magnetic materials. Children in particular are fascinated by magnetic toys that allow an object to be moved as a result of a magnetic field. Thus it is known to have a pair of play items each with a bar magnet attached to the underside (Brake, U.S. Pat. No. 2,249,454). Such items will attract one-another or repel one-another according to the orientation of the bar magnets to one-another.

SUMMARY OF INVENTION

An object of the present invention is to provide an improved magnetic toy. A further object of the invention is to provide a two piece toy where the pieces either attract or repel one-another merely as a result of varying the distance between the two pieces.

In one aspect the invention comprises a magnetic toy having two separate parts: a first part comprising a single magnet, and a second part comprising: at least one first magnet and and at least one second magnet; said first and second magnets being held in a fixed configuration one to another, such that the one or more first magnets produce a magnetic field that opposes the magnetic field of the one or more second magnets; the ratio of the pole strength of the single first magnet or the combined pole strengths of the plurality of first magnet to the pole strength of the single second magnets or the combined pole strengths of the plurality of second magnets being selected such that at some point a distance (X) of between 1 and 80 mm from said second part said opposing magnetic fields strengths are equal, resulting in zero field strength at said point. Preferably, this distance X is between 3 and 50 mm, and more preferably between 5 and 40 mm.

Preferably, the second part comprises a plurality of magnets; more preferably the second part comprises between 3 and 8 magnets; and most preferably between 5 and 7 magnets. Preferably, these magnets partially or fully surround said first magnet or group of first magnets and are equally spaced around said first magnet or group of said first magnets.

Preferably, the first and/or the second magnets have a fixed cross section along a first axis wherein this cross section is polygonal in outline/shape. Preferably, the first magnet and/or said second magnet is cylindrical in shape. More preferably, the depth (L1) of said cylinder is between 0.005 and 100 times the diameter (D1) of the cylinder. More preferably, the depth (L1) of said cylinder is between 0.01 and 50 times the diameter (D1) of the cylinder; and most preferably 0.1 to 10 times the diameter (D1) of the cylinder.

The first and second magnets may be cylindrical and have a depth L2 and L3 respectively such that the ratio of L2 to L3 is in the range 0.8 to 1.2.

A single second magnet may partially or totally surrounds said first magnet.

Preferably, the first and second magnets are held in said fixed configuration by a mounting frame or cradle. Preferably, the bases of the first part and second part are flat and the first and second parts are held in said fixed configuration one to another such that said flat bases lie on a single plane; this facilitates movement of the second part along a flat surface, such as a table top.

Preferably, the ratio of the combined pole strength of the first magnet or magnets (Si) to combined pole strength of the second magnet or magnets (S2) is in the range 1.0 to 100; and more preferably in the range 1.0 to 10; and most preferably in the range 1.0 to 2.

In another aspect the invention comprises a magnetic toy having two separate parts: a first part comprising a single magnet and a second part comprising a plurality of magnets held in fixed configuration to one another such that as the first part is moved towards the second part the magnetic force between the two parts will be such that they initially attract one another but at some point as the two parts become closer the direction of the magnetic force between the parts will reverse resulting in the two parts repelling one-another. Preferably, this will occur when the two parts are between 1 and 80 mm from one-another; and more preferably when the two parts are between 5 and 50 mm from one-another.

In a further aspect the invention comprises a magnetic toy having two separate parts: a first part comprising a single magnet, and a second part comprising: at least one first magnet and and at least one second magnet; said first and second magnets being held in a fixed configuration one to another, such that the one or more first magnets produce a magnetic field that opposes the magnetic field of the one or more second magnets; the ratio of the pole strength of the single first magnet or the combined pole strengths of the plurality of first magnet to the pole strength of the single second magnets or the combined pole strengths of the plurality of second magnets being selected such that as the first part is moved towards the second part the magnetic force between the two parts will be such that they initially attract one another but at some point between 1 and 80 mm (distance X) from each other this magnetic force will start to reverse resulting in the two parts repelling one-another. Preferably, this distance X is between 3 and 50 mm, and more preferably between 5 and 40 mm.

Preferably, one second magnet or a plurality of second magnets partially or fully surround a single said first magnet.

In use, the first and second part are normally placed on a flat surface such that these two parts are generally held in a single plane.

The second part may itself form part of a play item such as a vehicle or figure; for example the first and second magnets may be encased in the base portion of a figurine; that can then be moved over a flat surface in response to movement of the first part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 diagrammatically illustrate a toy according to the invention:

FIG. 1 shows a plan view of a preferred embodiment of the two-piece toy;

FIG. 2 shows a side view of the first and second magnets and their respective pole orientations:

FIG. 3 shows a more detailed plan view of the second part of the toy;

FIG. 4 shows a side elevation corresponding to FIG. 2;

FIG. 5 shows how the position of zero field strength varies with α;

FIG. 6 defines an angular parameter (α);

FIGS. 7( a) to 7(d) show alternative shapes (plan view) for the first part of the toy; and

FIGS. 8( a) to 8(h) show various alternative configurations for the first and second magnets (without a cradle) for the second part of the toy.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

A preferred embodiment of the invention will now be described by reference to FIGS. 1-4. FIG. 1 shows a magnetic toy (10) comprising a first part (12) with a single magnet, and a second part (14) comprising a plurality of magnets. In use, the first part of the toy (12) may be moved by means of the second part of the toy (14). One of both of these parts may be housed within or attached to a play article; such as an animal or vehicle. In use, the first part is moved (pulled or pushed) only by means of magnetic forces between the first and second part. Thus, in use there is no need for physical contact between the two parts. Thus, the two parts (12,14) attract or repel one-another merely as a result of varying the distance between the two parts.

The first part (12) may comprise simply a cylindrically shaped magnet.

In this preferred embodiment, the second part (14) comprises a central cylindrically shaped magnet (16) with six smaller cylindrically shaped magnets (18) held in a fixed configuration around the central magnet; in this case equally spaced around the perimeter. As illustrated (see FIG. 2, where the depth of the second magnets has been reduced for clarity of illustration) the six smaller surrounding magnets each have their South-poles uppermost and the larger central magnet has its North-pole uppermost. Thus, the magnetic field produced by the central magnet (16) opposes the magnetic fields produced by the six smaller surrounding magnets (18).

The surrounding magnets (18) can be bonded to the central magnet (16). However; it is preferable for the magnets to be held in their desired fixed configuration by means of a cradle or the like. FIGS. 2 and 3 show such a cradle (20). The cradle (20) comprises an inner hollow cylinder (22), surrounded by an outer hollow cylinder (24); the outer hollow cylinder (24) is held in a concentric position relative to the hollow cylinder (22) by means of six square frames (26). These frames are preferably spaced at equal intervals around the annulus formed between the inner cylinder (22) and the outer cylinder (24). The inner and outer cylinders may be attached to the six cradle frames (26) by any suitable means, such as adhesive, welds etc. The inner cylinder (22) is preferably sized such that the central magnet (16) is a tight push fit. Likewise, the six square cradle frames (26) and thus the outer cylinder (24) also are sized such that the six surrounding magnets (18) are also a tight push fit in the frames (26). Alternatively, the cradle frames may be circular or elliptical (plan view) in shape. Optionally, the cradle may have lower and upper disc-shaped covers attached thereto (not shown) that in use sandwich the above described (16, 18, 22, 24, 26) parts. Alternatively, the cradle and magnets may form the base portion of a figure or plaything.

The combination of magnets (16, 18) used in the second part (14) combined with their pole strengths; the orientation of their poles; and their relative placement results in the second part (14) producing an overall magnetic field that corresponds to a north-pole at a point in close proximity to the second part (14); the field strength rapidly decreasing to zero (at a point X mm from the second part) and at greater distances (than X) produces a magnetic field that corresponds to a south-pole.

In an example according to the above all of the magnets are cylindrically shaped and 6 mm deep. The central magnet (16) is 20 mm diameter and the surrounding magnets are 6 mm diameter. They are all neodymium magnets; the central magnet has a maximum lift of ca 6.6 kg and the surrounding magnets each have a lift of ca 1.1 kg. The first part (12) comprises a 20 mm diameter, 6 mm deep cylindrical neodymium magnet. For the above configuration FIG. 5 shows how the distance (measured from the centre of the central magnet) at which the field strength is zero varies with angular position (zero degrees corresponding to a straight line passing between the centre of the central magnet and the centre of a surrounding magnet). For clarity, FIG. 6 illustrates the above definition of angular position (α).

FIGS. 7( a) to 7(d) shows alternative shapes (plan view) for the first part (12).

FIGS. 8( a) to 8(h) show alternative configurations of the central magnet (16) and of the surrounding magnet (18) for the second part (14) according to further embodiments of the invention. Thus, a circular central magnet may be partially surrounded by 2, 5, 6, or 7 smaller cylindrical magnets (see FIGS. 8( a) to 8(d) respectively). A circular magnet may also be surrounded by an annular-shaped magnet (see FIG. 8( e)) or largely surrounded by a horseshoe-shaped magnet (see FIG. 8( f)). Alternatively a circular magnet may be partially surrounded by a plurality of non-circular magnets (see FIG. 8( g)). The central magnet need not be circular in cross section; for example it may be polygonal (see FIG. 8( h)) and in such cases the surrounding magnets may be polygonal in shape (cross section).

The second part is normally configured such that the circular-shaped (or polygonal) base faces of the first and second magnets lie on substantially a single plane. The bases of the first part and the second part lie on single plane. In use, the bases of the first part and the second part will normally be placed on a substantially planar surface; often a horizontal surface.

As the first part (12) is moved towards the second part (14) they will initially attract one-another, but eventually as they get closer (than distance X) they will repel one-another. Hence, when the two parts are on a flat surface, the first part can easily be used to move the first part in any direction without any danger of the two parts being pulled into contact with one-another as a result of their respective magnetic fields. 

1) A magnetic toy having two separate parts: a first part comprising a single magnet, and a second part comprising: at least one first magnet and at least one second magnet; said first and second magnets being held in a fixed configuration one to another, such that the one or more first magnets produce a magnetic field that opposes the magnetic field of the one or more second magnets; the ratio of the pole strength of the single first magnet or the combined pole strengths of the plurality of first magnet to the pole strength of the single second magnets or the combined pole strengths of the plurality of second magnets being selected such that at some point a distance (X) of between 1 and 80 mm from said second part said opposing magnetic fields strengths are equal, resulting in zero field strength at said point. 2) A magnetic toy according to claim 1 wherein the distance X is in the range 3-50 mm. 3) A magnetic toy according to claim 1 comprising a plurality of second magnets. 4) A magnetic toy according to claim 3 where the plurality of second magnets partially surround a single said first magnet or a group of said first magnets. 5) A magnetic toy according to claim 4 comprising at least three second magnets equally spaced around said first magnet or group of said first magnets. 6) A magnetic toy according to claim 1 where the first or the second magnets have a fixed cross section along a first axis and wherein this cross section is polygonal in outline/shape. 7) A magnetic toy according to claim 1 where said first or second magnet is cylindrical in shape. 8) A magnetic toy according to claim 7 where the depth (L1) of said cylinder is between 0.005 and 10 times the diameter (D1) of the cylinder. 9) A magnetic toy according to claim 7 where both the first and second magnets are cylindrical and have a depth L2 and L3 respectively such that the ratio of L2 to L3 is in the range 0.8 to 1.2. 10) A magnetic toy according to claim 1 wherein a single second magnet partially or totally surrounds said first magnet. 11) A magnet according to claim 1 where the first and second magnets are held in said fixed configuration by a mounting frame or cradle. 12) A magnetic toy according to claim 1 wherein the ratio of the combined pole strength of the first magnet or magnets (S1) to combined pole strength of the second magnet or magnets (S2) is in the range 1.0 to
 100. 13) A magnetic toy having two separate parts: a first part comprising a single magnet and a second part comprising at least one first magnet and at least one second magnet held in fixed configuration to one another, and the relative strengths of the magnets being such that as the first part is moved towards the second part the magnetic force between the two parts will initially result in attraction of the two parts but at some point as the two parts become closer the direction of the magnetic force between the parts will reverse resulting in the two parts repelling one-another. 14) A magnetic toy having two separate parts: a first part comprising a single magnet, and a second part comprising: at least one first magnet and at least one second magnet; said first and second magnets being held in a fixed configuration one to another, such that the one or more first magnets produce a magnetic field that opposes the magnetic field of the one or more second magnets; the ratio of the pole strength of the single first magnet or the combined pole strengths of the plurality of first magnet to the pole strength of the single second magnets or the combined pole strengths of the plurality of second magnets being selected such that as the first part is moved towards the second part the magnetic force between the two parts will be such that they initially attract one another but at some point between 1 and 80 mm from each other this magnetic force will start to reverse resulting in the two parts repelling one-another. 15) A magnetic toy according to claim 1 where one second magnet or a plurality of second magnets partially or fully surround said first magnet. 16) A magnetic toy according to claim 1 where the bases of the first part and second part are substantially flat and the first and second parts are held in said fixed configuration one to another such that said flat bases lie on a substantially single plane. 17) A magnetic toy according to claim 13 where one second magnet or a plurality of second magnets partially or fully surround said first magnet. 18) A magnetic toy according to claim 14 where one second magnet or a plurality of second magnets partially or fully surround said first magnet. 19) A magnetic toy according to claim 13 where the bases of the first part and second part are substantially flat and the first and second parts are held in said fixed configuration one to another such that said flat bases lie on a substantially single plane. 20) A magnetic toy according to claim 14 where the bases of the first part and second part are substantially flat and the first and second parts are held in said fixed configuration one to another such that said flat bases lie on a substantially single plane. 